Why do young feng shui masters rot?

The novel named "Young Feng Shui Master" is an urban supernatural novel written by the author Lan Benzun. The protagonist is Zheng Wu. The full text tells that Zheng Wu's grandfather was a master of Feng Shui. He grew up with his grandfather, so he also learned a lot of Feng Shui secrets. On the day of his grandfather's death, nine snakes came to Pima Dai Xiao to clear the way for him, which caused a sensation in the whole city. After his grandfather's death, Zheng Wu followed his grandfather's footsteps and became a man.